The influence of CNC machining position error on CNC machining accuracy. Position error refers to the degree of change or deviation of the actual surface, axis or symmetry plane of the processed part from its ideal position, such as perpendicularity, position, symmetry, etc. The position error in CNC machining usually refers to the dead zone error.
The main reason for the position error is the machining error caused by the clearance and elastic deformation of the transmission during the machining of the machine tool parts, and the position error caused by the friction force that the tool head needs to overcome during the machining process. In the open-loop system, the position accuracy is greatly affected, while in the closed-loop follow-up system, the position accuracy mainly depends on the displacement detection.
Machining accuracy errors caused by CNC machining geometric errors. In the processing of CNC machine tools, due to the influence of external factors such as external forces and heat generated during processing, the geometric accuracy of the machine tool is affected, and the geometric deformation of the parts processed on the machine tool will cause geometric errors. According to research, there are two main reasons for the geometric errors of CNC machine tools: internal factors and external factors.
The internal factors that cause machine tool geometric errors refer to the geometric errors caused by the machine tool itself, such as the levelness of the machine tool table, the levelness and straightness of the machine tool guide rail, and the geometric accuracy of the machine tools and fixtures. External factors mainly refer to geometric errors caused by external environment and thermal deformation during processing. For example, the geometric error caused by the thermal expansion and deformation of the tool or part during the cutting process will affect the machining accuracy of the machine tool and the part.
It can be seen from the long-term data analysis and actual operation of the part processing that the machining accuracy error caused by the positioning of the CNC machining machine tool. The positioning of the machine tool has a great influence on the machining accuracy of the CNC machine tool. From the structural point of view, the machining errors of CNC machine tools are mainly caused by the positioning accuracy, and the machine tool feed system is the main link that affects the positioning accuracy. The feed system of a CNC machine tool usually consists of a mechanical transmission system and an electrical control system.
In the structural design, the positioning accuracy is related to the mechanical transmission system. In the closed-loop system, the CNC machine tool can usually prevent the position deviation of the main components (such as ball screws and other components) in the feed system through the positioning detection device. However, for open-loop systems, due to many influencing factors and complex conditions, positioning monitoring cannot be performed, so the machining accuracy of CNC machine tools is greatly affected.